(a) Field of the Invention
The present invention relates to an improved wheel assembly, and particularly to a wheel assembly which limits direction of a housing thereof and simultaneously limits direction of the housing and a wheel thereof.
(b) Description of the Prior Art
A conventional wheel assembly often comprises a housing and a wheel pivoted on the housing. A pole is formed on an end of the housing for mounting on a bottom of an object. While the wheel rotates, the object moves. Meantime the pole of the housing may bring the wheel to rotate in multiple directions. So the object moves more easily to a predetermined position.
In this design, when the object moves, it bring the wheel to rotate in multiple directions, saving labor during movement of the object. However, ground of the predetermined position is not always flat, for example, it may be a slope. So people have to place obstruction between the wheel and the ground to stop the wheel. Sometimes people also place obstruction between the wheel and the ground to prevent the wheel from rotating. The obstruction often is just a stone, a brick, or some paper, which is picked up at random in the predetermined position. It is hard to stop the wheel and the object when there is nothing to act as obstruction.